Enhancing the Regeneration Performance of Methylene Blue Saturated Biochar in H2O2 System via Fe‐Doping

Abstract To improve the regeneration efficiency of methylene blue (MB) saturated biochar in H 2 O 2 system, biochar was modified by Fe‐doped by using FeSO 4 and Fe(NO 3 ) 3 as iron sources. The effects of Fe‐doped on its microstructure were characterized by XRD, SEM, and BET. The adsorption and regeneration performance of biochar before and after Fe‐doped were compared through adsorption and regeneration experiments. X‐ray photoelectron spectroscopy, electron spin resonance, and quenching experiments were used to explore the regeneration mechanism. The results show that Fe‐doped biochar (SP‐GBC) prepared from FeSO 4 maintains a high specific surface area of 1205.9 m 2 /g and a high adsorption capacity of 375.43 mg·g −1 for MB. After adsorption, the MB‐saturated SP‐GBC exhibits excellent regeneration performance in the H 2 O 2 system, in which the regeneration efficiencies for five consecutive cycles are 85.76%, 83.92%, 94.01%, 99.24%, and 100.79%, respectively. The synergistic effect of H 2 O 2 desorption and degradation is the main regeneration mechanism for MB‐saturated SP‐GBC. The zero valent iron and Fe (II) on the surface of SP‐GBC are the main active sites for H 2 O 2 activation, while 1 O 2 and HO· are the main oxidation species. In summary, this work provides a simple and feasible method for the design and synthesis of adsorbents with highly efficient regeneration performance.